Methods and apparatus for cleaning a substrate edge using chemical and mechanical polishing

ABSTRACT

Methods and apparatus are provided for concurrently chemically and mechanically polishing a substrate edge. The invention includes a substrate support adapted to rotate a substrate; a polishing head adapted to contact an edge of the substrate, the polishing head including a first channel adapted to apply a first fluid to the edge of the substrate; a second channel adapted to direct a second fluid onto a major surface of the rotating substrate; and a third channel adapted to direct a third fluid at the major surface of the substrate and to prevent the second fluid from diluting the first fluid. Numerous other aspects are provided.

The present application claims priority from U.S. Provisional PatentApplication Ser. No. 60/892,237 filed Feb. 28, 2007, entitled “SUBSTRATEEDGE BEVEL POLISHING SYSTEMS AND METHODS USING CHEMICALS FOR MATERIALREMOVAL” (Attorney Docket No. 11445/L).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is also related to the followingcommonly-assigned, co-pending U.S. patent applications, each of which ishereby incorporated herein by reference in its entirety for allpurposes:

U.S. patent application Ser. No. 11/299,295 filed on Dec. 9, 2005 andentitled “METHODS AND APPARATUS FOR PROCESSING A SUBSTRATE” (AttorneyDocket No. 10121);

U.S. patent application Ser. No. 11/298,555 filed on Dec. 9, 2005 andentitled “METHODS AND APPARATUS FOR PROCESSING A SUBSTRATE” (AttorneyDocket No. 10414);

U.S. patent application Ser. No. 11/693,695 filed on Mar. 29, 2007 andentitled “METHODS AND APPARATUS FOR POLISHING AN EDGE OF A SUBSTRATE”(Attorney Docket No. 10560);

U.S. Patent Application Ser. No. 60/939,351, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR POLISHING A NOTCH OF A SUBSTRATEUSING AN INFLATABLE POLISHING WHEEL” (Attorney Docket No. 10674/L);

U.S. Patent Application Ser. No. 60/939,353, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR FINDING A SUBSTRATE NOTCH CENTER”(Attorney Docket No. 11244/L);

U.S. Patent Application Ser. No. 60/939,343, filed May 21, 2007,entitled “METHODS AND APPARATUS TO CONTROL SUBSTRATE BEVEL AND EDGEPOLISHING PROFILES OF EPITAXIAL FILMS” (Attorney Docket No. 11417/L);

U.S. Patent Application Ser. No. 60/939,219, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR POLISHING A NOTCH OF A SUBSTRATEUSING A SHAPED BACKING PAD” (Attorney Docket No. 11483/L);

U.S. Patent Application Ser. No. 60/939,342, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR REMOVAL OF FILMS AND FLAKES FROM THEEDGE OF BOTH SIDES OF A SUBSTRATE USING BACKING PADS” (Attorney DocketNo. 11564/L);

U.S. Patent Application Ser. No. 60/939,350, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR USING A BEVEL POLISHING HEAD WITH ANEFFICIENT TAPE ROUTING ARRANGEMENT” (Attorney Docket No. 11565/L);

U.S. Patent Application Ser. No. 60/939,344, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR USING A ROLLING BACKING PAD FORSUBSTRATE POLISHING” (Attorney Docket No. 11566/L);

U.S. Patent Application Ser. No. 60/939,333, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR SUBSTRATE EDGE POLISHING USING APOLISHING ARM” (Attorney Docket No. 11567/L);

U.S. Patent Application Ser. No. 60/939,337, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR HIGH PERFORMANCE SUBSTRATE BEVEL ANDEDGE POLISHING IN SEMICONDUCTOR MANUFACTURE” (Attorney Docket No.11809/L);

U.S. Patent Application Ser. No. 60/939,212, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR IDENTIFYING A SUBSTRATE EDGE PROFILEAND ADJUSTING THE PROCESSING OF THE SUBSTRATE ACCORDING TO THEIDENTIFIED EDGE PROFILE” (Attorney Docket No. 11695/L);

U.S. Patent Application Ser. No. 60/99,228, filed May 21, 2007, entitled“METHODS AND APPARATUS FOR POLISHING A NOTCH OF A SUBSTRATE BY SUBSTRATEVIBRATION” (Attorney Docket No. 11952/L); and

U.S. Patent Application Ser. No. 60/939,209, filed May 21, 2007,entitled “METHODS AND APPARATUS FOR CONTROLLING THE SIZE OF AN EDGEEXCLUSION ZONE OF A SUBSTRATE” (Attorney Docket No. 11987/L).

FIELD OF THE INVENTION

The present invention relates generally to electronic device processing,and more particularly to methods and apparatus for cleaning an edge of asubstrate.

BACKGROUND OF THE INVENTION

During electronic device manufacturing, undesirable materials may buildup on the edge of a substrate. The materials may include dielectrics,photoresist and metals used in IC manufacture. Therefore, it may bedesirable to clean or polish the bevel and edge of the substrate toremove these materials. What is needed are systems, methods andapparatus for cleaning the edge of substrates without damaging the majorsurfaces of the substrates.

SUMMARY OF THE INVENTION

In aspects of the invention, an apparatus is provided for concurrentlychemically and mechanically polishing a substrate edge. The apparatuscomprises a substrate support adapted to rotate a substrate; a polishinghead adapted to contact an edge of the substrate, the polishing headincluding a first channel adapted to apply a first fluid to the edge ofthe substrate; a second channel adapted to direct a second fluid onto amajor surface of the rotating substrate; and a third channel adapted todirect a third fluid at the major surface of the substrate and toprevent the second fluid from diluting the first fluid.

In other aspects of the invention, a system is provided for concurrentlychemically and mechanically polishing a substrate edge. The systemcomprises a substrate support adapted to rotate a substrate; a polishinghead, adapted to contact an edge of a substrate, the polishing headincluding a first channel adapted to apply a first fluid to the edge ofthe substrate; a second channel adapted to direct a second fluid onto amajor surface of the rotating substrate; a third channel adapted todirect a third fluid at the major surface of the substrate and toprevent the second fluid from diluting the first fluid; and a controlleradapted to operate the concurrent chemical and mechanical polishing ofthe edge of the substrate.

In yet other aspects of the invention a method is provided forconcurrently chemically and mechanically polishing a substrate edge. Themethod includes the steps of (1) rotating a substrate; (2) contacting anedge of the substrate with a polishing head; (3) applying a first fluidto the edge of the substrate via the polishing head; (4) directing asecond fluid onto a major surface of the rotating substrate; and (5)directing a third fluid at the major surface of the substrate, whereinthe third fluid prevents the second fluid from diluting the first fluid.

Other features and aspects of the present invention will become morefully apparent from the following detailed description, the appendedclaims and the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic illustration of a cross-section of a portion of asubstrate.

FIG. 2 is a schematic illustration depicting an example embodiment of anedge cleaning system according to the present invention.

FIG. 3 is a perspective view depicting another example embodiment of anedge cleaning system according to the present invention.

FIG. 4 is a side view of a polishing unit according to the presentinvention.

FIG. 5 is a front view of a polishing unit according to the presentinvention.

FIG. 6 is a flow chart depicting an example application method ofembodiments of an edge cleaning system according to the presentinvention.

DETAILED DESCRIPTION

The present invention provides improved methods and apparatus forcleaning and/or polishing the edge of a substrate. The edge of asubstrate may be polished by application of an abrasive polishing pad orfilm contacting the substrate edge via a polishing head and byapplication of chemicals onto the substrate edge, as the substrate isrotated or otherwise moved (e.g., oscillated). As the substrate rotates,deionized water (hereinafter “DI water”) may be applied to the majorsurface (non-beveled and non-edge surface) of the substrate to preventpotential contamination and to remove material that accumulates as aresult of polishing/cleaning. However, it may be undesirable for the DIwater to contact the polishing head or dilute the chemicals. Accordingto the present invention, a curtain of fluid, and in a preferredembodiment a gas, such as N₂, is directed at the major surface of thesubstrate such that the gas prevents the DI water from contacting thepolishing head and/or diluting the polishing chemicals. In someembodiments the curtain of gas may be curbed to form an arc surroundingthe area on the substrate to be polished, such that the interior of thearc faces the polishing head. In some embodiments, the interior of thearc may face the DI water supply to contain the DI water and push itaway from the polishing head.

Turning to FIG. 1, a substrate 100 may include two major surfaces 102,102′, and an edge 104. Each major surface 102, 102′ of the substrate 100may include a device region 106, 106′, and an exclusion region 108,108′. (Typically however, only one of the two major surfaces 102, 102′will include a device region and an exclusion region.) The exclusionregions 108, 108′ may serve as buffers between the device regions 106,106′ and the edge 104. The edge 104 of a substrate 100 may include anouter edge 110 and bevels 112, 114. The bevels 112, 114 may be locatedbetween the outer edge 110 and the exclusion regions 108, 108′ of thetwo major surfaces 102, 102′. The present invention is adapted to cleanand/or polish the outer edge 110 and at least one bevel 112, 114 of asubstrate 100 without affecting the device regions 106, 106′. In someembodiments, all or part of the exclusion regions 108, 108′ may becleaned or polished as well.

Turning to FIG. 2, a schematic illustration of an example embodiment ofa polishing head system 200, including a polishing head 201, adapted topolish the edge 104 of a substrate 100 is provided. The substrate 100may be held or supported and rotated by a vacuum chuck 202, for example.Other suitable substrate support and rotation means may be used. Forexample, the substrate 100 may be rotated by driver rollers and guiderollers, etc. The polishing head 201 may include a backing pad 204, aroller, and/or an inflatable pad. In either case, the pad, roller and/orinflatable pad may be soft and/or include or develop contours to conformto the shape of the substrate edge 104. In some embodiments, the backingpad 204 may also include abrasive particles and be used to polish thesubstrate edge 104. Additionally or alternatively, the backing pad 204may be pressed against a polishing tape 206, used to polish thesubstrate edge 104. The system 200 may further include an actuator 208(e.g., a pneumatic slide, hydraulic ram, servo motor driven pusher,etc.). As the substrate 100 rotates, the actuator 208 may press thebacking pad 204, and hence the polishing tape 206, against the substrateedge 104. Alternatively or additionally, the actuator 208 may beadjustable, and may also be used to push the entire head 201 towards thesubstrate 100. Alternatively, a biasing device (e.g., a spring) may beemployed to mount the pad 204 to the head 201, to provideflexible/dynamic counter pressure to the pad 204. In some embodiments,the substrate 100 may be in contact with the polishing tape 206 forabout 15 to 150 seconds depending on the type of tape used, the grit ofthe tape, the rate of rotation, the amount of polishing required, etc.More or less time may be used. The contact between the polishing tape206, and the substrate edge 104, as the polishing tape 206 is pressedagainst the substrate edge 104 by the backing pad 204, combined with theparticular rotational speed of the substrate 100, may provide relativemovement between the polishing tape 206 and the substrate edge 104,resulting in polishing the substrate edge 104. Depending on the amountof force applied by the actuator 208, the resiliency of the pad 204selected, the amount of inflation of an inflatable pad, and/or theamount of tension on the polishing tape 206, a controlled amount ofpressure may be applied to polish the substrate edge 104. Thus, thesystem 200 may provide precise control of an edge polish process, whichmay be used to compensate for different edge geometries and changes inthe substrate 100 as material is removed from the substrate edge 104.

The pad 204 may be made of material such as, for example, an acetalresin (e.g., Delrin® manufactured by DuPont Corporation), PVDF,polyurethane closed cell foam, silicon rubber, etc. Other suitablematerials may be used. Such materials may have resilience or an abilityto conform that is a function of the thickness or density of the pad204. The material may be selected based upon its resilience. The desiredresilience may be selected based upon the type of polishing required.

In some embodiments, the degree to which the pad 204 may conform to thesubstrate edge 104 may be adjustable. For example, the pad 204 may be,or include, an inflatable bladder, as described in Application Ser. No.60/939,333 (Attorney Docket No. 11567/L), cited above, which may beinflatable by air, liquid or other fluid. The amount of fluid fillingthe pad 204 may be adjusted, such that the pad 204 may suitably conformto the substrate edge 104.

The substrate 100 may be rotated, for example, in a horizontal plane.The substrate edge 104 may be aligned with, or normal to, the polishingtape 206, pad 204 and/or polishing head 201. In additional oralternative embodiments, the substrate 100 may be rotated in a verticalplane, other non-horizontal plane, and/or be moved between differentplanes of rotation.

In the embodiment described herein, as the substrate 100 rotates, thepolishing head 201 may rock around the substrate edge 104 to polish theentire edge 104. The angle of rocking may include, for example, plus orminus 90 degrees. Other rocking angles may be used. In operation, thisis achieved by angularly translating the head 201, and consequently thebacking pad 204 and polishing tape 206 in contact with, and contouredto, the substrate edge 104, around an axis that is tangential to theouter edge 110 of the substrate 100 as it is rotated. In someembodiments, the head 201 may be adapted to continuously orintermittently oscillate between the various positions. The head 201 maybe moved by drivers (not shown) under the direction of a programmed oruser operated controller 210 (shown in FIG. 3). Alternatively, the head201 may be fixed and/or only adjusted while the substrate 100 is notbeing rotated. In yet other embodiments, the substrate 100 may be heldfixed while the head 201 is oscillated (as described above), as well asrotated circumferentially around the substrate 100. In some embodiments,the key parameters to control the edge polishing area may be the angleof rocking, the center of rotation for rocking, and the contour of thebacking pad.

In some embodiments, fluids or chemicals may be used to aid in thepolishing or washing away of accumulated particles, and may be deliveredto the substrate edge 104, as further described below with respect toFIG. 4.

As described above, in some embodiments, the controller 210 (shown inFIG. 3), (e.g., a programmed computer, a programmed processor, a gatearray, a logic circuit, an operator directed valve system, an embeddedreal time processor, etc.) may control the driver(s) used to rotate thesubstrate 100 and the actuator 208 used to push the pad 204 against thesubstrate edge 104. Note that the controller 210 may be coupled (e.g.,electrically, mechanically, pneumatically, hydraulically, etc.) to eachof a plurality of actuators 208. Likewise, operation of the fluidchannels, described below with respect to FIG. 4, may also be under thedirection of the controller 210. Under direction of the controller 210,various fluids may be selectively delivered to the pads 204 and/or thesubstrate edge 104 via the fluid channels. The controller 210 may beadapted to receive feedback signals from the driver and/or actuator 208,that indicate the amount of energy being exerted to drive the substrate100 (e.g., rotate a vacuum chuck holding the substrate 100) and/oractuate the actuator 208 to push the pad 204, respectively. Thesefeedback signals may be employed to determine when a particular layer offilm has been removed and/or whether a sufficient amount of polishinghas occurred.

FIG. 3 is a perspective view depicting an example embodiment of asubstrate polishing system 300 according to the present invention. Thesubstrate polishing system 300 shown herein includes three heads 302.Any number and type of heads 302 may be used in any practicablecombination. In addition, in such multi-head embodiments, each head 302may use a differently contoured backing pad 204 (e.g., differentcontours of the strip, etc.). Any number of heads 302 may be usedconcurrently, individually, and/or in a sequence. The heads 302 may bedisposed in different positions and in different orientations (e.g.,aligned with the substrate edge 104, normal to the substrate edge 104,angled relative to the substrate edge 104, etc.) to allow the pads 204and/or polishing tape 206 to polish different portions of the edge 104of the rotating substrate 100. The heads 302 may be adapted to beoscillated or moved (e.g., angularly translated about a tangential axisof the substrate 100 and/or circumferentially relative to the substrate100) around or along the substrate edge 104 by any suitable means so asto polish different portions of the substrate edge 104. Different heads302 may be used for different substrates 100 or different types ofsubstrates 100.

Turning to FIG. 4, a side view of a polishing unit 400 according to thepresent invention is depicted. In the example embodiment shown herein,the polishing unit 400 includes a polishing head 402. The polishing head402 may include a backing plate 404, covered by a backing pad 406. Insome embodiments the backing plate may be shaped to mimic the shape ofthe substrate while in other embodiments the backing plate may conformto the shape of the substrate. In some embodiments the backing plate 404may be coupled to the polishing head 402, while in other embodiments thebacking plate 404 may be integrally formed with the polishing head 402.The backing pad 406 may be used to mechanically polish the substrateedge 104. In some embodiments, as described above, polishing tape 206may be used to polish the substrate edge 104, and the backing pad 406(or roller) may press the polishing tape 206 against the substrate edge104. The polishing unit 400 may also include a nozzle 408, disposed atthe substrate edge 104. The nozzle 408 may be shaped as a thin curvedslit. Other nozzle shapes may be used. As described above, as thesubstrate 100 rotates, a deionized water supply may direct deionizedwater onto the major surface 102, 102 of the substrate 100, via adeionized water channel 410, and the deionized water may becentrifugally pushed out to the rest of the major surface 102, 102 ofthe substrate 100. Additionally, while the substrate 100 rotates, thenozzle 408 may dispense a curtain of fluid, such as N₂ (whereby thecurtain of fluid is hereinafter referred to as “N₂”). Other gases orfluids may be used. For example, other inert gases may be used. Theshape of the thin slit nozzle 408 may provide a curtain of N₂ betweenthe substrate edge 104 and the polishing head 402 and pad 406. In someembodiments the shape of the nozzle 408 may provide a curtain of N₂ thatmay be curved or arced, such that the area of the substrate 100 beingpolished, and a portion of the major surface 102 of the substrate 100,is surrounded by the N₂ curtain. This N₂ curtain may prevent thedeionized water from contacting, and potentially damaging, the polishinghead 402. Additionally, the N₂ curtain may also prevent the deionizedwater from mixing with, and diluting, the chemicals (described below andwith respect to FIG. 5) used to clean and polish the substrate edge 104.Alternatively, the N₂ curtain may prevent the chemicals (e.g., polishingchemicals) from contacting the major surface 102 of the substrate 100.The chemicals may include, for example, surfactant and/or other knowncleaning chemistries.

While in the exemplary embodiment shown here, the nozzle 408 ispositioned at a 90 degree angle with respect to the major surface 102 ofthe substrate 100, in alternate embodiments the nozzle may be positionedat a different angle with respect to the major surface 102 of thesubstrate 100. For example, when the nozzle 408 is perpendicular (or 90degrees) to the major surface 102 of the substrate 100, the N₂ curtainmay also flow in a perpendicular direction to the major surface 102 ofthe substrate 100. When the N₂ curtain contacts with the major surfaceof the substrate 100, it may flow towards both the polishing head 402and the DI water, thereby essentially pushing both the chemicals fromthe DI water to keep them separate. In another exemplary embodiment, thenozzle 408 may be angled towards the DI water, such that the N₂ curtainpushes the DI water away from the polishing head 402, further preventingchemical dilution, but may have no effect on the chemicals contactingthe substrate edge 104. In yet another exemplary embodiment, the nozzle408 may be angled towards the polishing head 402, such that the DI watermay be allowed to flow towards the polishing head 402, to a certainextent, but the chemicals are prevented from contacting the majorsurface 102 of the substrate 100.

In some embodiments the chemicals may be applied to and/or through thetape 206 and/or the pad 406 or roller. The backing plate 404 may includeone or more channels 502 adapted to drip or spray the fluid directlyonto or into the pads 204, 406. Alternatively, the pad 406 may beinflatable and may include a bladder (not shown) with a semi-permeablemembrane that allows fluid to be slowly released and transmitted to thepolishing tape 206 (e.g., through the pad). In such embodiments, the pad204, 406 may be covered by, made of, and/or include, material thatabsorbs and/or retains the fluids used (e.g., polyvinyl alcohol (PVA),etc.). In other embodiments, the chemicals may be sprayed directly ontothe substrate 100.

In an alternative embodiment, instead of a polishing pad 406 and/or incombination with the polishing pad 406, heating elements (not shown) maybe used to provide temperature assistance to enhance the wet etch rateof the chemicals used to polish/clean the substrate edge 104. Theapplied heat may be controlled at different locations to control theresulting material removal profile. As with the backing plate, thematerials that enclose the heating elements may be flexible/pliablematerials such as rubber, polyimide, etc.

Turning to FIG. 5, a front view of the polishing unit 400 described inFIG. 4, according to the present invention is depicted. In someembodiments, the polishing unit 400 may also include one or more sponges500. The sponges 500 may be affixed to the backing plate 404 andseparated by the polishing pad 406. Any suitable fixation means may beused. Other orientations may be used. Additionally, more or fewersponges 500 may be used. The backing plate 404, as described above, mayinclude one or more channels 502 adapted to supply a cleaning/polishingchemical to one or more of the sponges 500. In the particular exampledepicted herein, each sponge 500 is coupled to a separate channel 502.In some embodiments, for example, a single channel 502 may supplychemicals to multiple sponges 500, or an individual sponge 500 mayreceive chemicals from multiple channels 502. The chemicals may be thesame type or a different type. Different chemicals may be used to moreeffectively clean/polish the substrate. In either case, the sponge 500may receive different chemicals in sequence, for example. In otherwords, in the case of an individual sponge 500 and a single channel 502,a first chemical may flow through the channel 502 and then a second,different chemical may flow through the channel 502. In the case of theindividual sponge 500 and multiple channels 502, for example, a firstchemical may flow through a first channel 502 and then a second chemicalmay flow through a second channel 502. In the case of the individualsponge 500 with multiple channels 502, the sponge 500 may alternativelyreceive the chemicals from the multiple channels 502 at the same time.In some embodiments, the same chemicals may be flowed through themultiple channels 502 into the individual sponge 500 to increase theflow of chemicals to the sponge 500 and subsequently the substrate 100.In some embodiments, the same chemicals may be flowed through multiplechannels 502 into multiple sponges 500. Alternatively, each sponge 500may receive a different chemical. Additionally, the amount of chemicalssupplied to the sponges 500 may be controlled by the controller 210 oroperator. The sponges 500 may contact and apply chemicals to thesubstrate edge 104 during the cleaning/polishing process. Additionally,as described above, the polishing pad 406, similarly to the polishingtape described above, may include abrasive materials of various mineralsand grit sizes, which provide a mechanical polishing action. The thincurved slit nozzle 408 may be disposed at the substrate edge 104,between the substrate edge 104 and the sponges 500 and polishing pad406. While the substrate 100 rotates, as indicated by the central curvedarrow, and the deionized water is dispersed, the nozzle 408 may dispensea curtain of N₂, or other suitable gas (e.g., an inert gas). Asdescribed above, the curtain of N₂ is applied between the substrate edge104 and the sponges 500 and polishing pad 406, and may prevent thedeionized water from contacting and potentially damaging the polishinghead 402. Additionally, the N₂ curtain may also prevent the deionizedwater from mixing with and diluting the chemicals used to clean andpolish the substrate edge 104. Additionally, the N₂ curtain may alsoprevent the chemicals from contacting the major surface of thesubstrate.

Additionally, the present invention may employ gravity or suction tocause the runoff not to contaminate or contact other parts of thesubstrate 100 or system 200. Further, the substrate edge 104 may becleaned/polished by energy (e.g., megasonic energy), which may beapplied to the substrate edge 104 via fluid carrying such energy.

Turning to FIG. 6, a flow chart illustrating an exemplary method 100 ofthe present invention is depicted. Although five discrete sequentialsteps are depicted, it should be understood that any number of steps,sub-steps, and/or super-steps may be combined or divided out andperformed in different orders and/or concurrently. The particularsequence depicted is merely exemplarily and not necessarily required toperform various method embodiments of the present invention. In otherwords, for example, in some embodiments, all or some of the steps may beperformed concurrently or in reverse order. In step S102, a substrate isrotated in a chuck, for example. In step S104, an edge of the substrateis contacted with a polishing head. A first fluid, such as a cleaningchemical, is applied to the edge of the substrate via the polishing headin step S106. The chemical may be applied by sponges included in thepolishing head. In step S108 a second fluid is directed onto a majorsurface of the rotating substrate. The second fluid may be deionizedwater. As described above, as the substrate rotates, the water may becentrifugally pushed out to the rest of the major surface of thesubstrate. In step S110 a third fluid is directed at the major surfaceof the substrate, such that the third fluid prevents the second fluidfrom diluting the first fluid. The third fluid may be a curtain of N2.As described above, the curtain of N₂ is applied between the substrateedge 104 and the polishing head 402, and may prevent the deionized waterfrom contacting and potentially damaging the polishing head 402.Additionally, the N₂ curtain may also prevent the deionized water frommixing with and diluting the chemicals used to clean and polish thesubstrate edge 104. Additionally, the N₂ curtain may also prevent thechemicals from contacting the major surface of the substrate.

It should be understood that the inventive edge polishing apparatusdescribed herein may be employed in apparatuses other than those adaptedfor bevel and edge polishing and/or removal of films on substrates.Further, as will be apparent to those of ordinary skill in the art, theapparatus describe herein may be employed to polish and/or remove filmson an edge of a substrate supported in any orientation (e.g.,horizontal, vertical, diagonal, etc).

Further, it should be understood that although only examples of cleaninga round substrate are disclosed, the present invention could be modifiedto clean substrates having other shapes (e.g., a glass or polymer platefor flat panel displays). Further, although processing of a singlesubstrate by the apparatus is shown above, in some embodiments, theapparatus may process a plurality of substrates concurrently.

The foregoing description discloses only exemplary embodiments of theinvention. Modifications of the above disclosed apparatus and methodswhich fall within the scope of the invention will be readily apparent tothose of ordinary skill in the art. Accordingly, while the presentinvention has been disclosed in connection with exemplary embodimentsthereof, it should be understood that other embodiments may fall withinthe spirit and scope of the invention, as defined by the followingclaims.

1. An apparatus for concurrently chemically and mechanically polishing asubstrate edge, the apparatus comprising: a substrate support adapted torotate a substrate; a polishing head adapted to contact an edge of thesubstrate, the polishing head including a first channel adapted to applya first fluid to the edge of the substrate; a second channel adapted todirect a second fluid onto a major surface of the rotating substrate;and a third channel adapted to direct a third fluid at the major surfaceof the substrate and to prevent the second fluid from diluting the firstfluid.
 2. The apparatus of claim 1 wherein the first channel is furtheradapted to apply the first fluid to the edge of the substrate where thepolishing head contacts the edge.
 3. The apparatus of claim 1 whereinthe polishing head includes one or more sponges adapted to contact theedge of the substrate.
 4. The apparatus of claim 3 wherein the firstchannel provides the first fluid to the one or more sponges.
 5. Theapparatus of claim 1 wherein the polishing head includes a pad.
 6. Theapparatus of claim 1 wherein the polishing head includes a polishingtape.
 7. The apparatus of claim 1 wherein the polishing head includes aconformal backing plate.
 8. The apparatus of claim 1 wherein thepolishing head includes a shaped backing plate.
 9. The apparatus ofclaim 1 wherein the second fluid is deionized water.
 10. The apparatusof claim 1 wherein the shape of the third fluid forms an arc surroundingthe edge of the substrate contacted by the polishing head and a portionof the major surface of the substrate.
 11. A system for concurrentlychemically and mechanically polishing a substrate edge, the systemcomprising: a substrate support adapted to rotate a substrate; apolishing head adapted to contact an edge of a substrate, the polishinghead including a first channel adapted to apply a first fluid to theedge of the substrate; a second channel adapted to direct a second fluidonto a major surface of the rotating substrate; a third channel adaptedto direct a third fluid at the major surface of the substrate and toprevent the second fluid from diluting the first fluid; and a controlleradapted to operate the concurrent chemical and mechanical polishing ofthe edge of the substrate.
 12. The system of claim 11 wherein the shapeof the third fluid forms an arc surrounding the edge of the substratecontacted by the polishing head and a portion of the major surface ofthe substrate.
 13. The system of claim 12, further comprising a thincurved slit nozzle adapted to form the arc shape of the third fluid. 14.The system of claim 11 wherein the third fluid is N₂.
 15. The system ofclaim 11 wherein the controller is adapted to operate the direction ofat least one of the second and third fluids.
 16. The system of claim 11wherein the controller is adapted to operate the application of thefirst fluid to the edge of the substrate.
 17. The system of claim 11wherein the first channel is further adapted to apply the first fluid tothe edge of the substrate where the polishing head contacts the edge.18. The system of claim 11 wherein the polishing head includes one ormore sponges adapted to contact the edge of the substrate.
 19. Thesystem of claim 18 wherein the first channel provides the first fluid tothe one or more sponges.
 20. A method for concurrently chemically andmechanically polishing a substrate edge, the method comprising: rotatinga substrate; contacting an edge of the substrate with a polishing head;applying a first fluid to the edge of the substrate via the polishinghead; directing a second fluid onto a major surface of the rotatingsubstrate; and directing a third fluid at the major surface of thesubstrate, wherein the third fluid prevents the second fluid fromdiluting the first fluid.
 21. The method of claim 20 further comprising:arcing the third fluid such that the arc surrounds the edge of thesubstrate contacted by the polishing head and a portion of the majorsurface of the substrate.
 22. The method of claim 20 further comprising:rocking the polishing head about the edge of the substrate.
 23. Themethod of claim 20 further comprising: pressing a polishing tape againstthe edge of the substrate via the polishing head.
 24. The method ofclaim 20 further comprising: pressing a polishing pad against the edgeof the substrate via the polishing head.
 25. The method of claim 20wherein the polishing head includes at least one sponge, and the firstfluid is applied to the edge of the substrate via the at least onesponge.